Human, please tell hubby Thank you! I have one question (though I tend to agree with his observations) does he think the body being in a 'slick' type tarp would make it easier to fly out?
Another possibility is that the body is bundled up in such a way that it is "rounder", at least in one direction (like a cylander) and therefore more able to roll. I'm not saying it happened that way, just that I can imagine bundling causing a (6-year-old) body to roll out of a truck bed instead of sliding out.